/* 
 * Valid Palindrome
 * Given a string, determine if it is a palindrome, considering only alphanumberic characters and ignoring cases
 * For example:
 * "A man, a plan, a canal: Panama" is a palindrome
 */

#include "../func.h"

bool isPalindrome(string s)
{
    transform(s.begin(), s.end(), s.begin(), ::tolower);
    auto left = s.begin(), right = prev(s.end());

    while (left < right)
    {
        if (!isalnum(*left))
            ++left;
        else if (!isalnum(*right))
            --right;
        else if (*left != *right)
            return false;
        else
            left++, right--;
    }
    return true;
}